Hello
Sincerely
To do this procedure, you must create the iCloud account one month in advance
later, you must free that account, changing the email address, for another that ends in any other domain
This will be so that the account@icloud.com, is free, and, available to be used with your wife's Apple ID
then follow these steps
To change your appleID
You will not lose access to your contacts, purchases or other account information.
Go to
appleid.apple.com
and log in.
two.
In the Account section, select Edit.
3.
Choose "Change Apple ID."
Four.
Enter the email address you want to use.
5.
Select Continue.
6.
If you changed your Apple ID to a third-party email address, find the email that includes the verification code and enter it.
,
.
7.
If you use services like iCloud or Messages to share content with friends and co-workers,
sign in to those services with updated Apple ID
.
If you try to change your Apple ID to an email address ending in @ icloud.com created in the past 30 days, you may be asked to try again later.
If you see a message that the email address you want to use is not available or is already in use, check that you or a family member is not using that address with another Apple ID. If a family member uses that email address,
delete it
from her account and try to use it.
,
check the following resource
Change your Apple ID - Apple Support